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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
function IteratorIdentity() {
return this;
}
/* ECMA262 7.2.7 */
function IteratorNext(iteratorRecord, value) {
// Steps 1-2.
var result =
ArgumentsLength() < 2
? callContentFunction(iteratorRecord.nextMethod, iteratorRecord.iterator)
: callContentFunction(
iteratorRecord.nextMethod,
iteratorRecord.iterator,
value
);
// Step 3.
if (!IsObject(result)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, result);
}
// Step 4.
return result;
}
function GetIterator(obj, isAsync, method) {
// Step 1. If hint is not present, set hint to sync.
// Step 2. If method is not present, then
if (!method) {
// Step 2.a. If hint is async, then
if (isAsync) {
// Step 2.a.i. Set method to ? GetMethod(obj, @@asyncIterator).
method = GetMethod(obj, GetBuiltinSymbol("asyncIterator"));
// Step 2.a.ii. If method is undefined, then
if (!method) {
// Step 2.a.ii.1. Let syncMethod be ? GetMethod(obj, @@iterator).
var syncMethod = GetMethod(obj, GetBuiltinSymbol("iterator"));
// Step 2.a.ii.2. Let syncIteratorRecord be ? GetIterator(obj, sync, syncMethod).
var syncIteratorRecord = GetIterator(obj, false, syncMethod);
// Step 2.a.ii.2. Return CreateAsyncFromSyncIterator(syncIteratorRecord).
return CreateAsyncFromSyncIterator(syncIteratorRecord.iterator, syncIteratorRecord.nextMethod);
}
} else {
// Step 2.b. Otherwise, set method to ? GetMethod(obj, @@iterator).
method = GetMethod(obj, GetBuiltinSymbol("iterator"));
}
}
// Step 3. Let iterator be ? Call(method, obj).
var iterator = callContentFunction(method, obj);
// Step 4. If Type(iterator) is not Object, throw a TypeError exception.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_NOT_ITERABLE, obj === null ? "null" : typeof obj);
}
// Step 5. Let nextMethod be ? GetV(iterator, "next").
var nextMethod = iterator.next;
// Step 6. Let iteratorRecord be the Record { [[Iterator]]: iterator, [[NextMethod]]: nextMethod, [[Done]]: false }.
var iteratorRecord = {
__proto__: null,
iterator,
nextMethod,
done: false,
};
// Step 7. Return iteratorRecord.
return iteratorRecord;
}
/**
* GetIteratorFlattenable ( obj, stringHandling )
*
*/
function GetIteratorFlattenable(obj, rejectStrings) {
assert(typeof rejectStrings === "boolean", "rejectStrings is a boolean");
// Step 1.
if (!IsObject(obj)) {
// Step 1.a.
if (rejectStrings || typeof obj !== "string") {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, obj === null ? "null" : typeof obj);
}
}
// Step 2.
var method = obj[GetBuiltinSymbol("iterator")];
// Steps 3-4.
var iterator;
if (IsNullOrUndefined(method)) {
iterator = obj;
} else {
iterator = callContentFunction(method, obj);
}
// Step 5.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, iterator === null ? "null" : typeof iterator);
}
// Step 6. (Caller must call GetIteratorDirect.)
return iterator;
}
/**
* Iterator.from ( O )
*
*/
function IteratorFrom(O) {
// Step 1. (Inlined call to GetIteratorDirect.)
var iterator = GetIteratorFlattenable(O, /* rejectStrings= */ false);
var nextMethod = iterator.next;
// Step 2.
//
// Calls |isPrototypeOf| instead of |instanceof| to avoid looking up the
// `@@hasInstance` property.
var hasInstance = callFunction(
std_Object_isPrototypeOf,
GetBuiltinPrototype("Iterator"),
iterator
);
// Step 3.
if (hasInstance) {
return iterator;
}
// Step 4.
var wrapper = NewWrapForValidIterator();
// Step 5.
UnsafeSetReservedSlot(
wrapper,
WRAP_FOR_VALID_ITERATOR_ITERATOR_SLOT,
iterator
);
UnsafeSetReservedSlot(
wrapper,
WRAP_FOR_VALID_ITERATOR_NEXT_METHOD_SLOT,
nextMethod
);
// Step 6.
return wrapper;
}
/**
* %WrapForValidIteratorPrototype%.next ( )
*
*/
function WrapForValidIteratorNext() {
// Steps 1-2.
var O = this;
if (!IsObject(O) || (O = GuardToWrapForValidIterator(O)) === null) {
return callFunction(
CallWrapForValidIteratorMethodIfWrapped,
this,
"WrapForValidIteratorNext"
);
}
// Step 3.
var iterator = UnsafeGetReservedSlot(O, WRAP_FOR_VALID_ITERATOR_ITERATOR_SLOT);
var nextMethod = UnsafeGetReservedSlot(O, WRAP_FOR_VALID_ITERATOR_NEXT_METHOD_SLOT);
// Step 4.
return callContentFunction(nextMethod, iterator);
}
/**
* %WrapForValidIteratorPrototype%.return ( )
*
*/
function WrapForValidIteratorReturn() {
// Steps 1-2.
var O = this;
if (!IsObject(O) || (O = GuardToWrapForValidIterator(O)) === null) {
return callFunction(
CallWrapForValidIteratorMethodIfWrapped,
this,
"WrapForValidIteratorReturn"
);
}
// Step 3.
var iterator = UnsafeGetReservedSlot(O, WRAP_FOR_VALID_ITERATOR_ITERATOR_SLOT);
// Step 4.
assert(IsObject(iterator), "iterator is an object");
// Step 5.
var returnMethod = iterator.return;
// Step 6.
if (IsNullOrUndefined(returnMethod)) {
return {
value: undefined,
done: true,
};
}
// Step 7.
return callContentFunction(returnMethod, iterator);
}
/**
* %IteratorHelperPrototype%.next ( )
*
*/
function IteratorHelperNext() {
// Step 1.
var O = this;
if (!IsObject(O) || (O = GuardToIteratorHelper(O)) === null) {
return callFunction(
CallIteratorHelperMethodIfWrapped,
this,
"IteratorHelperNext"
);
}
var generator = UnsafeGetReservedSlot(O, ITERATOR_HELPER_GENERATOR_SLOT);
return callFunction(GeneratorNext, generator, undefined);
}
/**
* %IteratorHelperPrototype%.return ( )
*
*/
function IteratorHelperReturn() {
// Step 1.
var O = this;
// Step 2.
if (!IsObject(O) || (O = GuardToIteratorHelper(O)) === null) {
return callFunction(
CallIteratorHelperMethodIfWrapped,
this,
"IteratorHelperReturn"
);
}
// Step 3. (Implicit)
// Steps 4-6.
var generator = UnsafeGetReservedSlot(O, ITERATOR_HELPER_GENERATOR_SLOT);
return callFunction(GeneratorReturn, generator, undefined);
}
// Lazy %Iterator.prototype% methods
//
// In order to match the semantics of the built-in generator objects used in
// the proposal, we use a reserved slot on the IteratorHelper objects to store
// a regular generator that is called from the %IteratorHelper.prototype%
// methods.
//
// Each of the lazy methods is divided into a prelude and a body, with the
// eager prelude steps being contained in the corresponding IteratorX method
// and the lazy body steps inside the IteratorXGenerator generator functions.
//
// Each prelude method initializes and returns a new IteratorHelper object.
// As part of this initialization process, the appropriate generator function
// is called, followed by GeneratorNext being called on returned generator
// instance in order to move it to its first yield point. This is done so that
// if the `return` method is called on the IteratorHelper before `next` has been
// called, we can catch them in the try and use the finally block to close the
// underlying iterator.
/**
* Iterator.prototype.map ( mapper )
*
*/
function IteratorMap(mapper) {
// Step 1.
var iterator = this;
// Step 2.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, iterator === null ? "null" : typeof iterator);
}
// Step 3.
if (!IsCallable(mapper)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, mapper));
}
// Step 4. (Inlined call to GetIteratorDirect.)
var nextMethod = iterator.next;
// Steps 5-7.
var result = NewIteratorHelper();
var generator = IteratorMapGenerator(iterator, nextMethod, mapper);
UnsafeSetReservedSlot(
result,
ITERATOR_HELPER_GENERATOR_SLOT,
generator
);
// Stop at the initial yield point.
callFunction(GeneratorNext, generator);
// Step 8.
return result;
}
/**
* Iterator.prototype.map ( mapper )
*
* Abstract closure definition.
*
*/
function* IteratorMapGenerator(iterator, nextMethod, mapper) {
var isReturnCompletion = true;
try {
// Initial yield point to handle closing the iterator before the for-of
// loop has been entered for the first time.
yield;
// Not a Return completion when execution continues normally after |yield|.
isReturnCompletion = false;
} finally {
// Call IteratorClose on a Return completion.
if (isReturnCompletion) {
IteratorClose(iterator);
}
}
// Step 5.a.
var counter = 0;
// Step 5.b.
for (var value of allowContentIterWithNext(iterator, nextMethod)) {
// Steps 5.b.i-iii. (Implicit through for-of loop)
// Step 5.b.iv.
var mapped = callContentFunction(mapper, undefined, value, counter);
// Step 5.b.v. (Implicit through for-of loop)
// Step 5.b.vi.
yield mapped;
// Step 5.b.vii. (Implicit through for-of loop)
// Step 5.b.viii.
counter += 1;
}
}
/**
* Iterator.prototype.filter ( predicate )
*
*/
function IteratorFilter(predicate) {
// Step 1.
var iterator = this;
// Step 2.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, iterator === null ? "null" : typeof iterator);
}
// Step 3.
if (!IsCallable(predicate)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, predicate));
}
// Step 4. (Inlined call to GetIteratorDirect.)
var nextMethod = iterator.next;
// Steps 5-7.
var result = NewIteratorHelper();
var generator = IteratorFilterGenerator(iterator, nextMethod, predicate);
UnsafeSetReservedSlot(
result,
ITERATOR_HELPER_GENERATOR_SLOT,
generator
);
// Stop at the initial yield point.
callFunction(GeneratorNext, generator);
// Step 8.
return result;
}
/**
* Iterator.prototype.filter ( predicate )
*
* Abstract closure definition.
*
*/
function* IteratorFilterGenerator(iterator, nextMethod, predicate) {
var isReturnCompletion = true;
try {
// Initial yield point to handle closing the iterator before the for-of
// loop has been entered for the first time.
yield;
// Not a Return completion when execution continues normally after |yield|.
isReturnCompletion = false;
} finally {
// Call IteratorClose on a Return completion.
if (isReturnCompletion) {
IteratorClose(iterator);
}
}
// Step 5.a.
var counter = 0;
// Step 5.b.
for (var value of allowContentIterWithNext(iterator, nextMethod)) {
// Steps 5.b.i-iii. (Implicit through for-of loop)
// Step 5.b.iv.
var selected = callContentFunction(predicate, undefined, value, counter);
// Step 5.b.v. (Implicit through for-of loop)
// Step 5.b.vi.
if (selected) {
// Step 5.b.vi.1.
yield value;
// Step 5.b.vi.2. (Implicit through for-of loop)
}
// Step 5.b.vii.
counter += 1;
}
}
/**
* Iterator.prototype.take ( limit )
*
*/
function IteratorTake(limit) {
// Step 1.
var iterator = this;
// Step 2.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, iterator === null ? "null" : typeof iterator);
}
// Steps 3-6.
var integerLimit = std_Math_trunc(limit);
if (!(integerLimit >= 0)) {
ThrowRangeError(JSMSG_NEGATIVE_LIMIT);
}
// Step 7. (Inlined call to GetIteratorDirect.)
var nextMethod = iterator.next;
// Steps 8-10.
var result = NewIteratorHelper();
var generator = IteratorTakeGenerator(iterator, nextMethod, integerLimit);
UnsafeSetReservedSlot(
result,
ITERATOR_HELPER_GENERATOR_SLOT,
generator
);
// Stop at the initial yield point.
callFunction(GeneratorNext, generator);
// Step 11.
return result;
}
/**
* Iterator.prototype.take ( limit )
*
* Abstract closure definition.
*
*/
function* IteratorTakeGenerator(iterator, nextMethod, remaining) {
var isReturnCompletion = true;
try {
// Initial yield point to handle closing the iterator before the for-of
// loop has been entered for the first time.
yield;
// Not a Return completion when execution continues normally after |yield|.
isReturnCompletion = false;
} finally {
// Call IteratorClose on a Return completion.
if (isReturnCompletion) {
IteratorClose(iterator);
}
}
// Step 8.a. (Implicit)
// Step 8.b.i. (Reordered before for-of loop entry)
if (remaining === 0) {
IteratorClose(iterator);
return;
}
// Step 8.b.
for (var value of allowContentIterWithNext(iterator, nextMethod)) {
// Steps 8.b.iii-iv. (Implicit through for-of loop)
// Step 8.b.v.
yield value;
// Step 8.b.vi. (Implicit through for-of loop)
// Steps 8.b.i-ii. (Reordered)
if (--remaining === 0) {
// |break| implicitly calls IteratorClose.
break;
}
}
}
/**
* Iterator.prototype.drop ( limit )
*
*/
function IteratorDrop(limit) {
// Step 1.
var iterator = this;
// Step 2.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, iterator === null ? "null" : typeof iterator);
}
// Steps 3-6.
var integerLimit = std_Math_trunc(limit);
if (!(integerLimit >= 0)) {
ThrowRangeError(JSMSG_NEGATIVE_LIMIT);
}
// Step 7. (Inlined call to GetIteratorDirect.)
var nextMethod = iterator.next;
// Steps 8-10.
var result = NewIteratorHelper();
var generator = IteratorDropGenerator(iterator, nextMethod, integerLimit);
UnsafeSetReservedSlot(
result,
ITERATOR_HELPER_GENERATOR_SLOT,
generator
);
// Stop at the initial yield point.
callFunction(GeneratorNext, generator);
// Step 11.
return result;
}
/**
* Iterator.prototype.drop ( limit )
*
* Abstract closure definition.
*
*/
function* IteratorDropGenerator(iterator, nextMethod, remaining) {
var isReturnCompletion = true;
try {
// Initial yield point to handle closing the iterator before the for-of
// loop has been entered for the first time.
yield;
// Not a Return completion when execution continues normally after |yield|.
isReturnCompletion = false;
} finally {
// Call IteratorClose on a Return completion.
if (isReturnCompletion) {
IteratorClose(iterator);
}
}
// Step 8.a. (Implicit)
// Steps 8.b-c.
for (var value of allowContentIterWithNext(iterator, nextMethod)) {
// Step 8.b.i.
if (remaining-- <= 0) {
// Steps 8.b.ii-iii. (Implicit through for-of loop)
// Steps 8.c.i-ii. (Implicit through for-of loop)
// Step 8.c.iii.
yield value;
// Step 8.c.iv. (Implicit through for-of loop)
}
}
}
/**
* Iterator.prototype.flatMap ( mapper )
*
*/
function IteratorFlatMap(mapper) {
// Step 1.
var iterator = this;
// Step 2.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, iterator === null ? "null" : typeof iterator);
}
// Step 3.
if (!IsCallable(mapper)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, mapper));
}
// Step 4. (Inlined call to GetIteratorDirect.)
var nextMethod = iterator.next;
// Steps 5-7.
var result = NewIteratorHelper();
var generator = IteratorFlatMapGenerator(iterator, nextMethod, mapper);
UnsafeSetReservedSlot(
result,
ITERATOR_HELPER_GENERATOR_SLOT,
generator
);
// Stop at the initial yield point.
callFunction(GeneratorNext, generator);
// Step 8.
return result;
}
/**
* Iterator.prototype.flatMap ( mapper )
*
*/
function* IteratorFlatMapGenerator(iterator, nextMethod, mapper) {
var isReturnCompletion = true;
try {
// Initial yield point to handle closing the iterator before the for-of
// loop has been entered for the first time.
yield;
// Not a Return completion when execution continues normally after |yield|.
isReturnCompletion = false;
} finally {
// Call IteratorClose on a Return completion.
if (isReturnCompletion) {
IteratorClose(iterator);
}
}
// Step 5.a.
var counter = 0;
// Step 5.b.
for (var value of allowContentIterWithNext(iterator, nextMethod)) {
// Steps 5.b.i-iii. (Implicit through for-of loop)
// Step 5.b.iv.
var mapped = callContentFunction(mapper, undefined, value, counter);
// Step 5.b.v. (Implicit through for-of loop)
// Steps 5.b.vi.
var innerIterator = GetIteratorFlattenable(mapped, /* rejectStrings= */ true);
var innerIteratorNextMethod = innerIterator.next;
// Step 5.b.vii. (Implicit through for-of loop)
// Steps 5.b.viii-ix.
for (var innerValue of allowContentIterWithNext(innerIterator, innerIteratorNextMethod)) {
// Steps 5.b.ix.1-3 and 5.b.ix.4.a-b. (Implicit through for-of loop)
// Step 5.b.ix.4.c.
yield innerValue;
// Step 5.b.ix.4.d. (Implicit through for-of loop)
}
// Step 5.b.x.
counter += 1;
}
}
/**
* Iterator.prototype.reduce ( reducer [ , initialValue ] )
*
*/
function IteratorReduce(reducer /*, initialValue*/) {
// Step 1.
var iterator = this;
// Step 2.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, iterator === null ? "null" : typeof iterator);
}
// Step 3.
if (!IsCallable(reducer)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, reducer));
}
// Step 4. (Inlined call to GetIteratorDirect.)
var nextMethod = iterator.next;
// Steps 5-6.
var accumulator;
var counter;
if (ArgumentsLength() === 1) {
// Steps 5.a-d. (Moved below.)
counter = -1;
} else {
// Step 6.a.
accumulator = GetArgument(1);
// Step 6.b.
counter = 0;
}
// Step 7.
for (var value of allowContentIterWithNext(iterator, nextMethod)) {
if (counter < 0) {
// Step 5. (Reordered steps to compute initial accumulator.)
// Step 5.c.
accumulator = value;
// Step 5.d.
counter = 1;
} else {
// Steps 7.a-c and 7.e. (Implicit through for-of loop)
// Steps 7.d and 7.f-g.
accumulator = callContentFunction(reducer, undefined, accumulator, value, counter++);
}
}
// Step 5.b.
if (counter < 0) {
ThrowTypeError(JSMSG_EMPTY_ITERATOR_REDUCE);
}
// Step 7.b.
return accumulator;
}
/**
* Iterator.prototype.toArray ( )
*
*/
function IteratorToArray() {
// Step 1.
var iterator = this;
// Step 2.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, iterator === null ? "null" : typeof iterator);
}
// Step 3. (Inlined call to GetIteratorDirect.)
var nextMethod = iterator.next;
// Steps 4-5.
return [...allowContentIterWithNext(iterator, nextMethod)];
}
/**
* Iterator.prototype.forEach ( fn )
*
*/
function IteratorForEach(fn) {
// Step 1.
var iterator = this;
// Step 2.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, iterator === null ? "null" : typeof iterator);
}
// Step 3.
if (!IsCallable(fn)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, fn));
}
// Step 4. (Inlined call to GetIteratorDirect.)
var nextMethod = iterator.next;
// Step 5.
var counter = 0;
// Step 6.
for (var value of allowContentIterWithNext(iterator, nextMethod)) {
// Steps 6.a-c. (Implicit through for-of loop)
// Steps 6.d and 6.f.
callContentFunction(fn, undefined, value, counter++);
// Step 6.e. (Implicit through for-of loop)
}
}
/**
* Iterator.prototype.some ( predicate )
*
*/
function IteratorSome(predicate) {
// Step 1.
var iterator = this;
// Step 2.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, iterator === null ? "null" : typeof iterator);
}
// Step 3.
if (!IsCallable(predicate)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, predicate));
}
// Step 4. (Inlined call to GetIteratorDirect.)
var nextMethod = iterator.next;
// Step 5.
var counter = 0;
// Step 6.
for (var value of allowContentIterWithNext(iterator, nextMethod)) {
// Steps 6.a-c. (Implicit through for-of loop)
// Steps 6.d-g.
if (callContentFunction(predicate, undefined, value, counter++)) {
return true;
}
}
// Step 6.b.
return false;
}
/**
* Iterator.prototype.every ( predicate )
*
*/
function IteratorEvery(predicate) {
// Step 1.
var iterator = this;
// Step 2.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, iterator === null ? "null" : typeof iterator);
}
// Step 3.
if (!IsCallable(predicate)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, predicate));
}
// Step 4. (Inlined call to GetIteratorDirect.)
var nextMethod = iterator.next;
// Step 5.
var counter = 0;
// Step 6.
for (var value of allowContentIterWithNext(iterator, nextMethod)) {
// Steps 6.a-c. (Implicit through for-of loop)
// Steps 6.d-g.
if (!callContentFunction(predicate, undefined, value, counter++)) {
return false;
}
}
// Step 6.b.
return true;
}
/**
* Iterator.prototype.find ( predicate )
*
*/
function IteratorFind(predicate) {
// Step 1.
var iterator = this;
// Step 2.
if (!IsObject(iterator)) {
ThrowTypeError(JSMSG_OBJECT_REQUIRED, iterator === null ? "null" : typeof iterator);
}
// Step 3.
if (!IsCallable(predicate)) {
ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, predicate));
}
// Step 4. (Inlined call to GetIteratorDirect.)
var nextMethod = iterator.next;
// Step 5.
var counter = 0;
// Step 6.
for (var value of allowContentIterWithNext(iterator, nextMethod)) {
// Steps 6.a-c. (Implicit through for-of loop)
// Steps 6.d-g.
if (callContentFunction(predicate, undefined, value, counter++)) {
return value;
}
}
}